Conventional coin acceptors include a coin rundown path down which coins travel through a sensing station where sensors detect characteristics of the coin. Examples are described in our GB-A-2 169 429 and WO99/23615. Typically, inductive sensors are provided at the sensing station which perform inductive coin tests and produce coin parameter signals that are a function of the material and metallic content of the coin under test. Other sensors may be used, such as one or more optical sensors. The coin parameter signals are digitised and compared with stored coin data by means of a micro controller to determine the acceptability and often the denomination of the tested coin. If the coin is found to be acceptable, the micro controller operates an accept gate and the coin is directed to an accept path, but otherwise the accept gate remains closed and the coin is directed to a reject path.
The coin rundown path comprises an inclined rundown surface or flight deck, along which the coins roll edgewise through the coin sensing station, the flight deck being disposed between closely spaced, generally upwardly extending side walls which maintain the coin with its perimeter edge on the flight deck. One or both of the side walls may be inclined to the vertical so to encourage the coin under test to tip over whilst moving down the flight path, so that one of its major surfaces tends to slide along one of the side walls. This is intended to reduce wobbling of the coin on the rundown path. Coin wobble can vary the distance between the inductive sensors and successive coins as they pass through the sensing station, and produce an unwanted variation in the inductive coupling with the sensors from coin to coin as they are tested, which degrades the coin parameter signals.
Coins may become jammed in the coin rundown path. Conventionally, this problem has been addressed by moving the side walls apart to clear the jam. One of the sidewalls is formed as a part of the main body of the acceptor and the other side wall is defined by a surface on a door that is hinged on the main body. In the event of a coin jam, a release mechanism is operated to open the hinged door slightly, thereby moving apart the side walls so that the jammed coin can fall off the flight deck and into the reject path. The provision of a door however, undesirably adds to the manufacturing cost of the coin acceptor. Also, if the sensors are mounted on the door, a flexible wiring harness needs to be provided to accommodate the hinge and connect the sensors to the micro controller on the main body. The harness also adds to the manufacturing cost.